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Summer School 2020: Cover 3 Defense — what it is, and how to beat it

New York Giants Introduce New Head Coach Joe Judge Photo by Rich Schultz/Getty Images

Cover 3 is one of the most common coverages in the NFL today. There are many variations of the Cover 3, but it mainly consists of three deep and four underneath zones. Typically the deep zones are both corners, with the free safety in the middle of the field. Their responsibilities lie in the deep third of their respective zones. The four defenders underneath are spread out wide, and since the cornerbacks typically bail deep, the outside underneath defenders are put into a tough position to cover the flat.

Cover 3 can be employed from multiple personnel groupings on defense, but let’s say the defense is in nickel sub-package (five defensive backs). In that case, the nickel and strong safety would be tasked to eliminate the curl/flat (remember curl/flat means curl to the flat, so the defender’s first responsibility is the curl and then the flat). The linebackers would be in the hook zone, while the deep defenders drop to their depth, just like we see below:

Cover 3 puts an emphasis on the deep portions of the field. The corners play outside leverage and try to force the receivers inside towards the other zone defenders. Boxing the outside receivers in is one of the bigger advantages to Cover 3. If the corners are athletic enough and good in press, they can jam and bail, which could prevent quarterbacks from making quick easy throws to the flat.

Cover 3 allows a strong safety to drop into the box, which can also help against the run, and the coverage is also an excellent disguise coverage. The technique utilized by the underneath defenders can also be an advantage depending on the offense that they’re going up against. If an offense loves to control the intermediate middle of the field, then the linebackers can carry the routes further, forcing the quarterback into a tougher throw. This will, of course, lead to more underneath check downs, but could also force quarterbacks into turnovers.

One of the main goals of the defense is to force underneath throws that allow defenders to plant and drive downhill, effectively keeping the play in front of the defense, rather than behind it. There’s a reason why we’ve seen teams like the Seattle Seahawks, Atlanta Falcons, Los Angeles Chargers, and Jacksonville Jaguars have incredible defensive success in certain seasons, with the right personnel and coaching. The defense, when executed properly, can be very effective, but it still has its vulnerabilities.

Coverage vulnerabilities

An NFL field is 53 ⅓ yards wide, so having four underneath defenders guarding that much distance can be difficult. The biggest vulnerabilities of the Cover 3 are the flats, seams, and any route combinations that can hold certain defenders in place, while other offensive players manipulate the coverage. Cover 3 is also susceptible to horizontal, underneath, pass routes and the quick passing game.

As I stated earlier, the strong safety and nickel are put into a tough position to cover those curl/flat areas. Any type of out or immediate flat routes can expose the coverage and go for a good gain (daily fantasy fans: think of the Atlanta Falcons defense’s propensity to giving fantasy points to running backs in the receiving game). Lateral read routes are very hard to defend in a Cover 3 and they can really put defenders into conflict, especially those outside defenders. Curl/flat combinations from the offense are also tough to handle:

The nickel is in conflict above and has to make a choice between the hitch/curl or the running back flare, and this is from a two-receiver set. Slant/flats essentially do the same thing and can even pick the nickel and create a barrier (and become a blocker) for the running back to gain extra yardage after the catch. 3x1 sets can easily manipulate and flood Cover 3 with multiple routes where a defender’s choice will be wrong no matter what. 21 Personnel can also assist the offense in taking advantage of the middle of the field.

By running two angle routes to the middle of the field, with a tight end bending his seam to get behind the linebackers, before the safety, the offense creates a 3 vs. 2 isolation against the linebackers. Both the corner and the curl/flat defender would be occupied with the outside receivers deep curl. This is an excellent way to gain an advantage, but the throw must be quick, since the deep middle safety can drive down on the seam once the linebackers get sucked up by the running backs. Since those curl/flat defenders have to get lateral quickly, the inside two-on-one and three-on-two isolations really favor the offense.

Quick hitches out of a 2x2 set create ta pair of two-on-one isolations against the nickel and the strong safety. Again, the throws and reads need to be quick because corners can plant and drive downhill fast on the outside hitches. But against off-man coverage, this is a good way to pick up easy yardage, if the timing is right. The quick game can slice and dice Cover 3 badly, and this is why slant/flat, curl/flat, quick hitch, double speed out, and any other type of quick lateral read concept can be deadly to the coverage in the underneath game. Half field, 3x2 reads for quarterbacks are common against Cover 3.

With good pass protection, a play like this can have multiple advantageous decisions for a quarterback post snap. First off, the strong safety is forced into a two-on-one isolation in the curl/flat, but let’s say the middle linebacker and strong safety communicate and the strong safety flares to the flat, while the middle linebacker takes on the tight end (with poor leverage). To the weak side, the slot runs a deep horizontal cross, which would be right behind the middle linebacker who is covering the tight end’s stick route. This will prompt the free safety to bite down on the cross, a difficult task against a speedy wide out. The third read would then be the backside boundary receiver who runs his streak angled towards the goal post. Since Cover 3 plays with outside leverage, and the free safety bites downward on the cross, then that receiver has space, leverage, and one-on-one coverage outside. The reads have to be quick by the quarterback, but this could be an easy six points if the defense takes away the cross and stick/flare combo.

Cover 3 can also be manipulated deep with a sound play action game. Play action passes that draw linebackers close to the line of scrimmage provide a huge gap between the linebackers and the deep safety. A gap that can be exposed by deep crossing patterns. We went over the Yankee concepts in the Cover 1 article last week, the Yankee Concept is particularly effective against Cover 3, with a play action, because the deep crosser ends up in the vacated area left by the corner who is covering the 9 route. The free safety is forced to make a decision on jumping the horizontal cross, or allowing the 9 route wide receiver to angle his stem inward, giving him leverage against the cornerback.

When this play is run to the field, it can provide receivers ample space to operate. On this specific play, Earl Thomas gets held by the cross, which allows Will Fuller to easily beat the outside coverage for a deep touchdown. Another way to manipulate the deep free safety is to run hitch/seam patterns.


Hitch seams are a staple of the 2x2 Air Raid against Cover 3 defenses. The inside receivers stay on their seams and can slightly bend inside at about 20 yards. By that point, the quarterback would have made his decision and the middle of the field safety is put into conflict. Whichever way the safety goes, the quarterback throws to the other seam route. The quick hitches will draw the corners upward and can be hit right after the snap before the curl/flat defenders reach outside. Ideally, the X and Z would be lined up in plus splits here, to use maximum width of the field, which further stresses the defense. The Cover 3 can also be exposed by four-verticals which would obviously create a four-on-three isolation. This is one major reason why Nick Saban had to devise RIP/LIZ as the defensive coordinator for Bill Belichick in Cleveland; he had to come up with a defense that could drop eight men in the box, to stop the Steelers’ rushing attack, while still being able to play Cover 1 if the Steelers decided to run four vertical routes. Essentially, it was a way to play Cover 3 and Cover 1 at the same time, but was predicated on communication and decisive decision making from the defense based on the routes run by the offense.

Cover 3 is a zone defense, which means defenders can be high-lowed and flooded, so these are concepts that will be utilized all the time against any type of zone defense.

Similar to the curl/flat, a play like this forces the nickel back into conflict. The vertical slot has to be accounted for by either the deep corner or the free safety. If it’s the deep corner, then the nickel is left by himself with the comeback and the drag. Since it’s a deep comeback route, the corner may sit on the route, leaving the nickel to take the drag, which forces the free safety to cover the vertical slot. That’s all well and good, but the strong side receiver is running the deep post to a vacated area in the middle of the field, with great leverage against his deep corner. Yet another play that can exploit the continuity of a solid defensive structure. Hook zone defenders are not averse to being high-lowed either:

Both hook zone defenders are in conflict here, but especially to the weak side. The dig/snag combo attacks the OLB’s zone and puts him into conflict. One of those two routes should be open no matter what, but the MLB is also in conflict. A lot of linebackers are taught to carry the seam route to a certain depth, which gives the free safety an opportunity to recognize and put himself into position, since the seams tend to be vulnerable against Cover 3. If that’s the case, the quick slant acts as a replacement route and a window should be open underneath the deep inside linebacker who carried the seam. This is a double two-man route combination that put defenders into tough positions. Drive concepts, with a running back sitting just outside the tackle box will also create a three-on-two advantage for the offense against the hook defenders, as would a cross concept (similar to drive, but the shallow cross comes from the opposite side of the dig). Texas concept, a very good route against man coverage, can also have its advantages against the hook zone defenders in a Cover 3 defense:

We see the strong side running back with a bit wider split, to give him an extra step on his route. The tight end angles inward to catch the eye of the middle linebacler, who would then carry the tight end up the field. The strong safety would cheat his coverage outside, as the running back looks to be heading towards the flat. The strong side receiver runs a comeback to occupy the corner, and the running back would have a huge alley with the middle linebacker following the tight end’s route and the outside linebacker gaining depth on the weak side post. This is an excellent way to clear-out the middle of the field and allow a running back like Saquon Barkley to catch the ball in space against a zone defense. Football is a puzzle and coverage pieces can be manipulated, especially from overloaded sets like the 3x1, but there are ways to gain advantages against a base Cover 3 defense.

One of the more common ways to defeat zone coverages is to flood the zone with more receivers than the defense can handle. This play above would be a half field read for the quarterback; he reads the strong safety, who is put into conflict because of the tight end’s out route and the running back in the flat. The corner is occupied with the vertical and the middle linebacker is too far away to make a realistic impact on the flood. These types of route combinations are very common against Cover 3, and it’s one reason why you’d probably should check out of Cover 3 if you’re going against a 3x1 set.

Attacking the seams and the flats are the easiest ways to take advantage of cover 3. Creating two-on-one or three-on-two isolations, along with high/low reads, while putting players in conflict is one of the essences to manipulating any type of zone coverage, so Cover 3 is left vulnerable when an offense does this effectively. The route combinations above are just some of the popular ways the offenses can find, or create, voids against the Cover 3 defense. Quick game half field lateral reads are a very effective way to attack the defense. There are a lot of different types of Cover 3 defenses, so variations can take away one type of offensive concept, but that leaves something else open to attack.

For example, Cover 3 cloud disguises as a Cover 2 defense and it’s a way to play three deep, with Cover 2 technique at the line of scrimmage from a corner (typically the strong safety would rotate deep, with one corner jamming and bailing to the deep 1/3); the defense can play underneath a backside receiver and over the top. Defenses would do this against Odell Beckham Jr. constantly when he was on the Giants. If you’re aware of the technique being played on a star receiver, then you can utilize your other receivers to take advantage of a coverage that is trying to take away the most dangerous threat. A lot of football is a give and a take, with adjustments throughout. Cover 3 has its advantages for sure, but a good, well-timed, offense can pick the underneath defenders apart, especially with the right route combinations to manipulate specific defenders; this is one of the many reasons why speed is so essential at the linebacker position. Cover 3 is still, and should continue to be, an excellent base coverage for many skilled NFL teams that have the necessary personnel.